1. Field of the Invention
The present invention relates to a high-frequency surgical apparatus and to a high-frequency surgical method for closure of patent foramen ovale, where the high-frequency surgical apparatus and high-frequency surgical method are used to perform high-frequency surgery by applying a high-frequency current to the living tissues of patent foramen ovale in the heart.
2. Description of the Related Art
Generally, high-frequency surgical apparatus are known which cause living tissues adhere to each other using high-frequency power. When high-frequency power is applied to living tissues from such a high-frequency surgical apparatus, Joule heat generated by a high-frequency current flowing through the living tissues heats the living tissues. The living tissues have the property of denaturing and consequently adhering to each other when heated sufficiently.
There is a condition known as patent foramen ovale (PFO) in the heart. The PFO is a flaplike gap existing in part of the atrial septum which separates the left atrium from the right atrium. Normally, the pressure in the left atrium is higher than the pressure in the right atrium, so that the valvula foraminis ovalis is pressed against the atrial septum, and thereby the PFO is closed. However, severe coughing or tension (due to pressure on the lungs) can reverse the pressure difference, temporarily opening the flap.
Blood may contain blood clots developed in the body. Normally, the blood returning to the right atrium from the body is sent to the lungs where a blood clot is removed. However, it may happen that the instant the PFO opens, a blood clot that flow into the right atrium passes through the PFO and is sent back into the body. If the blood clot reaches the brain, it can cause cerebral infarction. Thus, it is desirable to close the PFO.
A conventional technique, International publication No. WO 2007/100067 discloses a high-frequency surgical apparatus used to close a PFO. The conventional technique includes grasping means made up of a needle member and grasping member. Both the needle member and grasping member act as high-frequency electrodes. After a PFO is grasped with the two members, high-frequency power is applied to the two electrodes to heat the PFO by Joule heat and thereby close the PFO.